【作者】 李宝良；

【导师】 兆文忠；

【作者基本信息】 大连交通大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 机械零件的磨损一直是摩擦学界的研究热点之一。光面磨损是最常见的复合磨损形式,由于这种磨损具有缓慢的渐进性特点,对机械系统的性能影响与突发性相比往往容易被忽视,但其危害性却很大。目前,国内外对磨损的研究主要集中在实验研究方面,并已取得了大量成果。但是,实验研究需要大量的人力、物力、财力,所获得的结论也具有很强的应用条件性。另一方面,摩擦学工作者一直致力于将摩擦学研究成果应用于工程设计,但是效果并不明显。这也是因为摩擦学理论还未达到象经典力学理论一样应用于工程设计的程度,即使经典的磨损理论也很难直接与工程中所希望的磨损寿命预测、磨损动态过程监测和耐磨性设计相联系。随着摩擦学学科的发展,“计算摩擦学”正日益显示其强大的生命力。计算摩擦学就是将数值仿真技术应用到磨损研究中,以期预测零件的磨损寿命、指导摩擦副耐磨性优化设计。数值仿真是一种离散数学和计算机技术相结合的新技术,已广泛应用于工程领域并取得了优良的成果。本文就是通过对线接触零件摩擦副磨损数值仿真,考虑温度、压力等因素,建立磨损数值仿真模型,并将可靠性理论引入到数值仿真模型中,以期提供一种线接触零件磨损寿命预测、指导耐磨性优化设计方法。本文主要研究内容：(1)接触模型建立要建立磨损仿真的数学模型,首先要清楚赫兹接触区的压力分布规律,求解出赫兹接触区接触压力,为后续的仿真模型建立奠定基础。(2)材料磨损率的研究综合分析影响材料磨损的各种因素,选择具有适用范围广泛的实验方法,通过实验及实验数据处理、参数修正等方法,考虑压力、温度、润滑等因素影响获得线接触零件的材料磨损率通用公式。(3)线接触零件磨损仿真模型的建立基于数值仿真的基本思想,将连续的单个零件磨损过程离散化,在每一个离散单元中将动态过程准静态化,制定磨损数值仿真的算法方案,同时在磨损进程中,充分考虑磨损变位情况,作为下一步磨损计算的依据。(4)磨损寿命可靠性估算仿真算法建立对于磨损寿命预测迄今普遍仍采用固定值,这是不科学的。机械系统的抗磨损寿命具有显著的概率特征,考虑载荷、速度等参数以及磨损渐发性过程所具有的随机分布特性,应用蒙特卡洛法概率理论,建立磨损寿命可靠性估算算法,编制磨损概率寿命通用软件。(5)线接触典型零件仿真实例模型建立及仿真分析利用建立的磨损仿真通用模型,对凸轮机构系统、轴承机构系统和齿轮机构系统磨损数值仿真及可靠性寿命估算,为其进一步耐磨优化设计提供支持。本文得到国家自然基金项目《基于数值仿真的系统磨损概率寿命设计理论和方法研究》(项目编号：50375022)的资助。更多还原

【Abstract】 Wear of mechanical parts has been one of the research focuses in the field of tribology. Smooth wear is the most common form of composite wear. Because this kind of wear has the feature of slow gradualness, the impact brought by the smooth wear to the properties of mechanical systems is often neglected as compared with unexpected wears. But it has great hazard.At present, domestic and foreign research on wear is mainly focused on experimental research. And it has got a lot of achievements. However, experimental research requires a lot of manpower, material and financial resources, and the conclusions obtained have strong application conditionalities. On the other hand, tribology researchers have been committed to apply the research achievements of tribology to engineering design. But the effect is not obvious, because the tribology theory has not achieved the being applied level in engineering design as classical mechanics theory. It is even very difficult for the classical wear theory to be directly connected with wear life prediction, wear dynamic process monitoring and abrasion resistance design in engineering projects as hoped.As the development of tribology,’computational tribology’has been showing its strong vitality increasingly. Computational tribology is to apply the numerical simulation technology to the study of wear, in order to predict the wear life of parts and direct the optimal design of abrasion resistance for friction pairs. Numerical simulation is a new technology combined with discrete mathematics and computer technology. It has been widely applied in engineering and achieved excellent results.In this paper the wear numerical simulation model will be established through making numerical simulatiing for the wear of friction pairs of line contact parts, taking factors such as temperature, pressure, etc. into consideration. Then by introducing the reliability theory into the numerical simulation model, a method will be provided in order to predict the wear life of line contact parts and direct the optimal design of abrasion resistance for friction pairs.The main research contens of this paper are:(1) The establishment of contact modelIn order to establish the mathematical model for wear simulation, the pressure distribution law of the Hertz contact area has to be known at first. Then the contact pressure of the Hertz contact area has to be solved in order to lay the foundation for the subsequent establishment of the simulation model.(2) Research on the material wear rateBy analysing various factors affecting wear of materials comprehensively, and selectting experimental methods that have broad scope of applications, the general formula for the material wear rate of line contact parts will be obtained through experiments and methods such as experimental data processing, parameter correction, etc., taking consideration of the factors such as pressure, temperature, lubrication, etc.(3) The establishment of the simulation model for the wear of line contact partsBased on the basic idea of numerical simulation, the continuous wear process of a single part will be made discrete, and the dynamic process will be made quasi-static in each discrete element. Meanwhile, the wear displacement situation will be taken into full account in the wear process as the basis for the subsequent wear claculation.(4) The establishment of the simulation algorithm of the reliability estimation for the wear lifeSo far, fixed values are still being generally used for the prediction of wear life. But it is not scientific. The wear life of mechanical systems has significant probability features. By using the probability theory of Monte-Carlo method, the algorithm of the reliability estimation of the wear life will be established and the general software for the wear probability life will be prepared, taking the parameters such as load, velocity, etc. and the random distribution features of the wear process of gradual onset into consideration.(5) The establishment of simulation models and the simulation analysis for typical line contact partsBy using the established general wear simulation model, the wear numerical simulation and probability life estimation for the cam mechanism systems, bearing mechanism systems and gear mechanism systems will be established in order to support the further optimal design in abrasion resistance.This paper is supported by the project of National Natural Science Foundation of China—"Research of theory and methods for design of probability wear life of systems based on numerical simulation"(Project Number:50375022).更多还原